Methane may be mainly formed through thermogenic and methanogenic (biogenic) processes. Biogenic methane may be believed to consist of about 20-40% of the total methane storage on earth, and higher ratios (such as about 65%) under favorable bio-geological conditions. Methanogens may be strictly anaerobic archaebacteria. Biogenic methane production may be carried out by methanogens through methanogenesis, in which carbon dioxide and small organic molecules may be converted to methane through a series of biological reactions perhaps by microbial populations as those skilled in the art can appreciate. Isotope fractionation studies may have verified that biogenic methane is actively produced in coal seam and oil shale and the like, which may contain a rich source of small organic compounds to serve as substrates for methanogenesis. Accordingly, methanogenesis can produce methane from oil shale, coal, coal derivatives, lignite, and the like by removing hydrogen and carbon from a source.
Methane production processes may be a versatile biotechnology capable of converting almost all types of polymeric materials to methane and carbon dioxide under anaerobic conditions. This may be achieved as a result of the consecutive biochemical breakdown of polymers to methane and carbon dioxide in an environment in which a variety of microorganisms which may include fermentative microbes (acidogens); hydrogen-producing, acetate-forming microbes (acetogens); and methane-producing microbes (methanogens) harmoniously grow and produce reduced end-products. Anaerobes may play important roles in establishing a stable environment at various stages of methane production.
Coal bed methane (“CBM”), as an example, may demonstrate that CBM water overlaying coal seam may be able to support observable methane production under anaerobic conditions. Methane production may not have been observed in sterile controls, possibly confirming it may be a microbially mediated process. Indigenous methanogens have been detected as present in the coal cores extracted from the Powder River Basin (PRB), indicating a potential of enhancing the methanogenic activities as an economically feasible approach to harvest bioreservoir of CBM.
Currently, an effective technology to identify and enhance biogenic methane production in coal seam, oil shale, and the like may be lacking. For example, U.S. Pat. No. 6,543,535 to Converse, hereby incorporated by reference, includes analysis of subterranean formations and stimulating activity of microbial consortia based on the analysis in a subterranean formation to convert hydrocarbons to methane. However, applicability of enhancement of biogenic methane production to a wide variety of situations and even efficient enhancement of biogenic methane is desired in the industry.